The present invention relates to a matrix display device, representative of which is an active matrix liquid crystal display device, and in particular to a matrix display device capable of color display.
In a conventional active matrix display device for example, an externally inputted video signal which has an arrangement of Mxc3x973 (RGB)xc3x97N is displayed, as shown in FIG. 10, by a matrix display section (display element) 58 which is made up of Mxc3x973 signal lines, N scanning lines, and display cells each of which is a portion enclosed by the signal lines and the scanning lines. Note that, in xe2x80x9cMxc3x973 (RGB)xc3x97Nxe2x80x9d, xe2x80x9c3 (RGB)xe2x80x9d refers to a numerical value 3 according to three different colors: red (R), green (G) and blue (B).
Further, in this active matrix display device, as shown in FIG. 9, each one pixel 51 is made up of three cells 52 (52a to 52c), one of which is red (R), another is green (G) and the other is blue (B). In each cell 52, a ratio of the length in a horizontal direction (xe2x80x9chorizontal lengthxe2x80x9d, hereinafter) to the length in a vertical direction (xe2x80x9cvertical lengthxe2x80x9d, hereinafter) is as follows: the horizontal length:the vertical length=1:3. Namely, as shown in FIG. 9, when the horizontal length of the cell 52 is Sx2, and the vertical length thereof is Sy2, Sx2:Sy2=1:3.
Further, since each pixel 51 includes three cells 52 disposed side by side in the horizontal direction, the pixel 51 has the shape of a square. More specifically, as shown in FIG. 9, when the horizontal length of the pixel 51 is Px2, and the vertical length thereof is Py2, Px2 (=3xc3x97Sx2):Py2 (=Sy2)=1:1. With this arrangement, when displaying a xe2x80x9ccirclexe2x80x9d for example, display shows the xe2x80x9ccirclexe2x80x9d but not an xe2x80x9cellipsexe2x80x9d.
Furthermore, a wiring pitch of the Mxc3x973 signal lines 53 and the N scanning lines 54 that are disposed in a matrix shows the following ratio: a pitch of the signal line 53:a pitch of the scanning line 54=1:3.
The foregoing conventional matrix display device that includes the pixel 51, the signal line 53 and the scanning line 54 has an arrangement as shown in FIG. 10, for example. FIG. 10 shows the case where the pixels 51 are provided, the number of which is calculated as follows: M (the number of pixels in a horizontal direction)xc3x97N (the number of pixels in a vertical direction). An arrangement shown in FIG. 10 is as follows: each signal line 53 is connected to a signal line driving circuit 55; each scanning line 54 is connected to a scanning line driving circuit 56; the signal line driving circuit 55 is supplied with a video signal and a control signal from a control circuit 57; and the scanning signal line driving circuit 56 is supplied with a control signal from the control circuit 57.
Here, for ease of explanation, FIG. 11 shows a low-resolution matrix display device in which the number of the pixels 51 is calculated as follows: M (horizontal direction)=3, and N (vertical direction)=2. This display device has a basic arrangement as with FIG. 10. Further, FIG. 12 is a timing chart of various signals in the signal line driving circuit 55 shown in FIG. 11.
As shown in FIG. 12, the signal line driving circuit 55, in a timing {circle around (1)} of DOT_CK, makes sampling of each cell 52 of the pixel 51, for example, in an upper left-hand corner in FIG. 11, that is, video data of three individual systems respectively corresponding to R (0,0), G (0,0) and B (0,0). The sampling data are applicable to signals of three systems Sr(0), Sg(0) and Sb(0) to be outputted to the signal line 53. Likewise, at timings {circle around (2)} and {circle around (3)}, there is made sampling of video data of three individual systems respectively corresponding to R (1,0), G (1,0) and B (1,0), and R (2,0), G (2,0) and B (2,0). These sampling data correspond to signals of three systems Sr(1), Sg(1) and Sb(1), and Sr(2), Sg(2) and Sb(2), respectively, that are outputted to the signal line 53.
Thus, the signal line driving circuit 55 finishes sampling of one scanning portion of video data (video data of the three individual systems) which corresponds to a scanning line G(0) (scanning line 54), thereafter outputting the signals Sr, Sg and Sb of the three individual systems corresponding to these sampling data to each signal line 53. Likewise, the signal line driving circuit 55 makes sampling of one scanning portion of video data (video data of the three independent systems) which correspond to a next scanning line G(1) at timings {circle around (4)}, {circle around (5)} and {circle around (6)}, so as to output the signals Sr, Sg and Sb of the three independent systems corresponding to these sampling data to each signal line 53.
Since the video signal is a digital signal, in the case of an arrangement of FIG. 11, when, for example, a video signal of RGB 8 bits is adopted, 3 systems (Sr, Sg and Sb)xc3x978 bits, thereby requiring 24 sampling circuits.
However, in the foregoing conventional arrangement, a signal line has a pitch which is three times smaller than that of the scanning line 54 and is an extremely small pitch. Therefore, when attempting to realize a high-definition panel, from the view points of a panel design rule and/or a driver connection rule, a high-definition panel cannot be developed.
For example, when designing a high-definition panel having display density of about 200 dpi based on the foregoing conventional arrangement, one pixel 51 becomes 120 xcexcmxe2x96xa1 (120 xcexcmxc3x97120 xcexcm), and therefore, each cell 52 and each signal line 53 has the pitch of 40 xcexcm. Further, commonly, the pitch of connection between each output terminal of the signal line driving circuit 55 and each signal line 53 is measured the same as the wiring pitch of the signal line 53. However, according to the currently existing technology, the acceptable finest pitch in the connection is 50 xcexcm, and therefore, the pitch of about 40 xcexcm as above cannot be adopted.
Note that, Japanese Unexamined Patent Publication No. 95027/1996 (Tokukaihei 8-95027 published on Apr. 12, 1996) discloses an arrangement in which a ratio of a cell pitch in a horizontal direction to a cell pitch in a vertical direction is set at a predetermined value. Japanese Unexamined Patent Publication No. 72826/1995 (Tokukaihei 7-72826 published on Mar. 17, 1995) discloses an arrangement in which cells composing one pixel are disposed in the shape of a letter L. However, neither of these techniques aims to loosen the tight pitch of a signal so as to attain high-definition display, and moreover, simply using these techniques cannot solve the foregoing problems.
For example, the following process is disclosed in the Publication No. 72826/1995. When performing display of a video signal having the resolution (800xc3x973(RGB)xc3x97600) by a display device having the different resolution of XGA (1024xc3x973(RGB)xc3x97768) for example, the pseudo-interpolation and enlargement of the resolution causes the edges of an image to be unclear. Therefore, in this conventional invention, though one pixel is normally made up of three cells R, G and B, yet the number of cells to compose a pixel is variable in accordance with the inputted resolution, thereby preventing the edges of an image from being unclear in a plurality of resolutions. More specifically, in the same Publication, when inputting a signal having the resolution of FIG. 2(A), one pixel is given one of each of the cells R, G and B. Further, when inputting a signal having the resolution of FIG. 2(B), one pixel is given two of each of the cells R, G and B, namely, six cells in total.
In view of the foregoing problems, it is an object of the present invention to provide a matrix display device capable of high-definition display that was not reached by conventional technology, by a low-cost arrangement in which a small pitch of a signal line is made larger so as to allow a connection pitch of the signal line to be larger.
In order to attain the foregoing object, a matrix display device according to the present invention which has a plurality of signal lines and a plurality of scanning lines crossing one another, and a plurality of pixels each one of which includes three cells of first, second and third colors, wherein:
when the cells of first to third colors composing one pixel are first to third cells in an arbitrary sequence, the second cell is disposed on one side of the first cell in a direction orthogonal to the signal lines (xe2x80x9csignal line alignment directionxe2x80x9d, hereinafter) while disposing the third cell on the other side of the first cell in a direction orthogonal to the scanning lines (xe2x80x9cscanning line alignment directionxe2x80x9d, hereinafter), and the first to third cells form the shape of a letter L,
one pixel and another pixel adjacent to either one side of the former pixel in the scanning line alignment direction are a first pixel in the shape of the letter L and a second pixel in the shape of the letter L and in a state rotating by 180xc2x0 with respect to the first pixel, respectively, the first and second pixels being paired with each other and disposed so that the combination of the two pixels form a square, and
all the first pixels have the same combination of colors of the first to third cells, and all the second pixels have the same combination of colors of the first to third cells.
With the foregoing arrangement, the number of cells in the signal line alignment direction and the number of signal lines can be reduced. This realizes a wider connection pitch between the signal line driving circuit and the signal line while allowing a wiring pitch of the signal line and the connection pitch between the signal line driving circuit and the signal line to be smaller, thereby producing a high-definition matrix display device.
Note that, thus having the smaller wiring pitch of the scanning line and connection pitch between the scanning line and the scanning line driving circuit raises no problems because these pitches are originally set to be larger than pitches on the side of the signal lines.
Additional objects, features, and strengths of the present invention will be made clear by the description below. Further, the advantages of the present invention will be evident from the following explanation in reference to the drawings.